.app{
	width: 100%;
	height: 100vh;
	background-color: #ffffff;
	position: relative;
	display: flex;
	justify-content: center;
	align-items: center;
}
.btn45{
	width: 48px;
	height: 48px;
	background-color: #333;
	cursor: pointer;
	position: relative;
	border-radius: 6px;
	transform: rotate(15deg);
}
.btn45:before{
	content: '';
	width: 48px;
	height: 48px;
	background-color: #333;
	border-radius: 6px;
	position: absolute;
	transform: rotate(45deg);
}
.btn45:after{
	content: '';
	width: 16px;
	height: 16px;
	background-color: #333;
	border: 8px solid #ffffff;
	border-radius: 50%;
	position: absolute;
	left: 50%;
	top: 50%;
	transform: translate(-50%,-50%);
}
.btn45:hover{
	animation: eff45 2s linear infinite;
}
@keyframes eff45{
	100%{
		transform: rotate(375deg);
	}
}